Silver is utilized as an electrically conductive filler in many commercially available electrically conductive coatings, and encapsulants because its oxide is electrically conductive, and therefore, silver filled systems encounter little or no loss of conductivity during high temperature curing, aging, or other conditions under which the silver may be oxidized. A disadvantage of the use of silver is its high cost and the risk of silver migration within the system.
The high level of conductivity and low resistance provided by entirely silver-filler based products are not necessary for all conductive material applications. Some applications do not require such high levels of conductivity and low resistance. Copper is another conductive material that may be utilized because it is capable of being processed in forms similar to those in which silver is available, i.e., in powder, dendritic and flake form. The main disadvantage of copper is that its oxide is not conductive, and any surface copper oxide formed during drying or curing limits the conductivity of the system even if close interparticle contact is created. Likewise, many other materials that provide electrical conductivity oxidize under the conditions necessary for formation of a conductive coating.
There continues to be a need in the art for a more economical electrically conductive composition. The present invention addresses this need.